An attack by Iran on military bases in Iraq struck sites containing British and American personnel.
The United States said 15 missiles were fired towards the Al Asad air base and a base in Erbil, with no casualties having been reported among US or UK personnel.
The attack was launched in response to a US air strike that killed top Iranian general, Qassem Soleimani.
Al Asad is around 100 miles west of Iraq's capital, Baghdad.
The base plays a major role in the US-led coalition that trains Iraqi and Kurdish Security Forces to fight so-called Islamic State (IS).
Roughly 1,500 US military, plus hundreds more from other coalition nations, are stationed at the base.
In 2018, US President Donald Trump and First Lady Melania Trump made a surprise Christmas visit to Al Asad - it was Mr Trump's first time in a combat zone as President and Commander In Chief.
Erbil - the capital city in Iraq's northern Kurdish region - is much closer to the Iran border than Al Asad.
The base is also considerably smaller than Al Asad and is attached to Erbil International Airport, where within it is a small British military camp.
Similar to Al Asad and most of the bases in Iraq, the area where troops are housed is actually very small, but is surrounded by vast training areas.
What Is It Like Inside Erbil?
In 2015, Forces News correspondent Simon Newton visited the US base at Erbil to report on the work of the British Army training teams based there.
He said: "It isn’t a 'base' in the traditional sense, it’s almost a bolt on to the city’s International Airport.
"Mosul is just an hour-and-a-half drive away, and when we visited, it was still under IS control.
"There was a lot of US airpower based there – Apaches, Ospreys – and a lot of flying going on.
"It’s a key base for training the Kurdish Peshmerga who were really instrumental in holding back Daesh in those early years.
"The base was predominantly American, but within it was a small UK camp, housing around 100 British troops.
"They had their own social area, accommodation and offices but also used the US facilities, such as the dining hall and gym - the same arrangement they have in most big bases in Iraq.
"Close by was a large training area, including firing ranges and mock buildings where the UK troops taught the Peshmerga military skills and tactics.
"At that time they were preparing for a future assault on Mosul, so the focus was very much on counter-IED techniques."
British troops are also deployed to two other bases in Iraq - Camp Taji near Baghdad and Union III in Baghdad.
In total, around 400 British Army soldiers are based in the country in a non-combat role.
However, the UK's training mission was suspended on Saturday amid heightened threat levels.
On Tuesday, the UK sent a support team to Iraq to help with the British military contingency plan that includes evacuation.
Cover image: British troops in Erbil, Iraq, in 2016 (Picture: US Army).